Members of the genus Bordetella cause highly infectious respiratory tract infections of a variety of warm-blooded animal hosts, including humans. Much recent work has focused on the pathogenesis of B. pertussis, the causative agent of whooping cough, but little is understood about B. avium and its role in bordetellosis in birds, particularly turkeys. The key pathological manifestation of bordetellosis is the colonization and destruction of ciliated cells in the respiratory epithelium. Thus, this study will focus on chicken or turkey tracheal ring culture to study the effects of B. avium on ciliated tissue. The first specific aim is to isolate mutants of B. avium that have lost various cell surface components and toxins. These will subsequently be characterized for the ability to adhere and/or cause pathological changes to the tracheal tissue. Interesting mutants identified by these screens will be further characterized by standard molecular genetic approaches. The second specific aim (which will actually be carried out first) is to further characterize turkey and chick tracheal rings as a model system for studying B. avium pathogenesis. Methods for quantifying adherence will be tested.